NEW YORK STATE FIRST OF SEVERAL UNUSUAL U.S. EARTHQUAKES TODAY

LATE BREAKING NEWS

The strongest solar flare since Oct 22, 2001 hit about an hour
ago just as the strong geomagnetic storm was returning to quiet
conditions. A strong proton storm followed this flare. Sub-solar
latitudes at the time of the flare were about 170E, anti-solar
locations at 10W. Areas within about 30 degrees longitude of either
of these longitudes will experience the greatest effects from this
flare and are under seismic watch conditions for the next two days.
High latitudes and areas along the geomagnetic equator are also likely
to see increased seismicity in the next two days. The effect of this
flare is uncertain coming at the end of a strong geomagnetic storm.
Many of the events which were ripe for geomagnetic triggering have
already had earthquakes. Nevertheless, strong earthquakes could still
accompany these storms and this X1.2 flare between April 21 and April
25. This watch includes areas of New Zealand, Kermadec, Tonga, Samoa,
the Aleutians and western Europe.

Following is a listing of X-flares since 2000:

June 6, 2000 X 1.1, X2.3
June 7, 2000 X 1.2
June 18, 2000 X 1.0
July 11, 2000 X 1.0
July 12, 2000 X 1.9
July 14, 2000 X 5.7
Sept 30, 2000 X 1.2
Nov 24, 2000 X 2.0, X2.3
Nov 25, 2000 X 1.8
Nov 26, 2000 X 1.9
Mar 2, 2001 X 1.7
Apr 2, 2001 X20.0, X1.4, X1.1
Apr 3, 2001 X 1.2
Apr 6, 2001 X 5.6
Apr 10, 2001 X 2.3
Apr 12, 2001 X 2.0
Apr 15, 2001 X14.1
Apr 24, 2001 X 2.6
May 23, 2001 X 1.2
Aug 25, 2001 X 5.3
Oct 19, 2001 X 1.2
Oct 22, 2001 X 1.6
Oct 25, 2001 X 1.1
Nov 4, 2001 X 1.0
Nov 22, 2001 X 1.0
Nov 25, 2001 X 1.1
Apr 21, 2002 X 1.2

While not included in the watch area, the region of Central California
along the coast often responds to large solar flares with locally
significant earthquakes. This is an area currently under watch from
other effects and an X1.6 flare at this time is not helpful in reducing
the seismic risk in this area.

SUMMARY

A moderate earthquake shock the northeastern U.S. this morning.
This event occurred along the border between New York and Vermont
and has Mb 5.1 (NEIS) or MN 5.5 (GSC). It is the strongest earthquake
within 50 km of this epicenter ever recorded. It was followed by
aftershocks of Ml 4.0 and 2.6.
The earthquake did minor damage in the epicentral area (Lake Placid)
and was felt from Buffalo, New York to Boston to Maine, Massachusetts
and Maryland.
The earthquake was probably an FFA from Mexico and Chile being 36
degrees from the first and 72 degrees from the second. The area of
the northeast and New York had been identified in the FFA forecast
as an area where FFA were likely. The daily summary had also noted
that strong effects in this area are often associated with strong
geomagnetic storms.
The geomagnetic storm this morning reached extremely powerful conditions
at about 05:00-06:00 UT (midnight at the epicenter), so effects from
that storm were maximized at the epicenter of the earthquake just
hours before the earthquake occurred. Geomagnetic triggering also
seems to have played a major role in the timing of this event.
Eight hours later a Ml 3.0 (CERI) hit the New Madrid, Missouri
area. This area had also been expected to see FFA from Chile and was
near the edge of the region which was under seismic watch due to the
powerful geomagnetic storms which were still active at the time of
this event. This is the largest New Madrid earthquake since July
14, 2001.
The third unusual earthquake of the day occurred near Randolph, Utah.
This event at 22:18 UT occurred in a region of relatively low seismicity
in northern Utah. The last event which was clearly larger in a 35 km radius
of today's epicenter occurred on Sept. 30, 1995. The epicenter was
in an area under seismic watch conditions at the time of the earthquake.

GLOBAL

Global seismicity was at moderately high levels today. The largest
event was a non-destructive Mb 5.9 in the Fiji Islands region this morning.
The area had been under seismic watch conditions at the time of the
earthquake.
An earthquake of Ml 5.6 (TMA) (MB 4.9 NEIS) also occurred south of
Taiwan two hours before the New York earthquake. Other areas which
were active today were the Hokkaido/Okhotsk Sea/Kuril area where
earthquakes of Mb 4.4 and Mj 4.8 (5.2 CSEM) were registered.
The most active global area appeared to be the region south of
Mindanao from the Celebes to Halmahera. Three moderate earthquakes
occurred in this area today at the Talaud Islands (M 5.1 GSSC);
Mindanao (Mb 5.1 GSSC) and the Celebes Sea (Mb 4.5 GSSC).

U.S./CANADA

The major earthquakes of the U.S. and Canada were discussed in
the summary above and included the Mn 5.5, 4.0 and 2.6 on the
New York/Vermont border; the Ml 2.6 near Randolph Utah and the Ml
3.0 (Mb 2.8 NEIS) in the New Madrid region.
A fourth earthquake of Ml>=3.0 occurred in the region of northern
California, also at the height of the geomagnetic storm this morning.
This event was identified as near Eureka or SSW of Willow Creek, CA.
It was preceded by an Ml 2.7 to the southeast near Anderson, CA earlier.
The only other event of Ml>=2 in the California/Nevada region occurred
near Loma Rica (Ml 2.0), also in northern California slightly less than
4 minutes before the Willow Creek earthquake. It is possible there
may have been a triggering effect at Willow Creek from this Loma Rica
event.
No earthquakes of Ml>=3 were listed in Alaska or Hawaii today. The
only other event listed with Ml in the 2.0 range was a Ml 1.9 near
Darrington, northern Washington which also occurred near the height
of the geomagnetic storm.
The geomagnetic storm abated about 15:00 UT and conditions throughout
the U.S. have been relatively quiet since the storm diminished.

NEW ZEALAND

IGNS reported an Ml 3.7 near Porangahau this afternoon. Otherwise
the region appears to have been relatively quiet seismically today.

The IGNS on-line Seismometer can be found at:
http://www.gns.cri.nz/news/earthquakes/latest_drum.html

GEOMAGNETIC/SOLAR FIELDS

An extremely strong geomagnetic storm reaching Kp 9 and high-latitude
AA indices > 110 maximized this morning between 05:00 UT and 10:00 UT.
This is the strongest storm (AP 63) by far since November 6, 2001.
Seismic effects apparently included the largest earthquake ever to
occur along the northern New York/Vermont border.
The storm gradually dimished through the rest of the day until a
strong X1.2 solar flare occurred on the morning of April 21, 2002.
This is the strongest flare in half a year and is expected to also
result in moderate to strong increases in seismicity near the
International Date Line, in particular. Flare parameters are
preliminary as listed:

Flare # START MAX END CLASS

0043 0151 0238 X1.6

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20020420events.txt
http://sec.noaa.gov/ftpdir/indices/events/20020421events.txt

TIDAL EFFECTS

April 22 is the ninth day after the beginning of the new lunar month.
Regions most likely to experience tidal triggering
on this day (With associated magnitude ranges; the percent change in
seismicity rate over background seismicity rate on this
day of the lunar month; statistical z-value and
significance level) are:

Region Magnitude range %change z-value Significance level

Mt ST. Helens MB>=1.0 55 4.1 0.01
Washington MB>=3.0 19 3.3 0.01
JMA MB>=4.0 14 2.0 0.05

Regions expected to experience reverse triggering (i.e. they are
unlikely to experience a significant event at this period of the
lunar cycle) are:

Region Magnitude range %change z-value Significance level

East US MB>=1.0 -12 -2.3 0.04

TOMORROW IN EARTHQUAKE HISTORY

GLOBAL:

The following events of Mw>=7 have occurred on this date in
recorded history:

MO DA HR MN SC YEAR LATIT LONGIT DEP MW LOCATION

4 21 11 30 0 1916 32.500 141.800 60 7.1 Off East Coast Honshu
4 21 13 56 22 1916 36.500 70.500 220 7.1 Hindu Kush/Pakistan
4 21 0 49 49 1917 37.000 70.500 220 7.0 Hindu Kush/Pakistan
4 21 4 29 4 1939 47.500 139.800 520 7.0 So. Kurils
4 21 20 22 2 1948 19.250 -69.250 40 7.3 Puerto Rico
First shock was moderate, second, third and last were
also moderate. All four shocks were felt throughtout the island.

4 21 21 12 30 1957 6.960 -72.200 33 7.1 Colombia
150 houses destroyed at Tachiro, 20 houses at Arboledas, felt
at Caracas, Venezuela

4 21 4 24 10 1977 -9.965 160.731 33 8.1 No. of Santa Cruz Islands
4 21 0 30 11 1995 11.925 125.564 17 7.2 Luzon, Philippines
Some damage occurred at Borongan and Sulat. Felt from Davao, Mindanao to
Cebu. It triggered a 20 cm tsunami.

4 21 12 2 26 1997 -12.584 166.676 59 7.9 Vanuatu Islands
4 21 12 6 34 1997 -12.881 166.464 33 7.9 Vanuatu Islands
Earthquake caused significant damage to the islands of Hiu, Tegua and Lo.
Torre Isnands and Ureparapara in the Bank islands of Vanuatu. It was
followed by a tsunami that washed away seven houses and destroyed
three others. No injuries or fatalities although the tsunamis was
registered at 7 to 15 meters above the concrete buildings.

U.S./CANADA

Following are events of Mb>=5 which have occurred in this region on

MO DA HR MN SC YEAR LATIT LONGIT DEP MW LOCATION

4 21 17 43 0 1892 38.600 -121.900 0 6.5 Central California
At Winters, CA. Although the total energy expended was probably less,
the intensity was as great as that on April 19. The shock was most
severe at Winters, about 12 miles north of Vacaville. Many buildings
which withstood the previous shock were leveled to the ground.
On Main Street, not a building was left which could be occupied. The
buildings were constructed mostly of brick or stone. At Esparto
every brick chimney was toppled. Damage was reported from Vacaville,
to Resno and as far east as Reno NV.

4 21 22 32 25 1918 33.750 -117.000 0 6.8 So. California
At Riverside County, San Jacinto and Hemet suffered heavy damage.
Only one new concrete and one frame building were left standing
in the business district of San Jacinto. The buildings wrecked were
of brick or artificial stone and old. Well constructed buildings
were not heavily damaged. Property loss in the two places was
estimated at $200,000. The shock occurred on Sunday afternoon,
as loss of life was minimized. Numerous cracks were found in the
road betwen the two towsn. Concrete irrigation canals were broken
in a number of places.
Damage also occurred at Redlands, Riverside and San Bernardino, and
as far away as Los Angeles. Roads in the epicentral area were
closed to traffic by slides, and one automobile was swept off
the road by a slid. Great clouds of dust arose from the mountains
and water flow and spring changes were commonplace. Sand and mud
craters were formed. In the region of the San Jacinto Fault southeast
of Hemet the dry earth surface was broken up as though be a plow.

4 21 21 26 42 1961 51.700 -173.900 36 5.6 Andreanoff Islands, Aleutians
4 21 5 1 36 1964 61.500 -147.300 38 5.4 Central Alaska
4 21 6 42 16 1971 53.850 -161.518 21 5.4 Unimak Islands, Aleutians
4 21 1 28 8 1972 53.947 -166.819 91 5.8 Fox Islands, Aleutians
4 21 15 4 54 1985 55.880 -154.940 33 5.0 Southern Alaska
4 21 15 25 16 1985 55.770 -155.030 33 5.6 Alaska Peninsula
4 21 15 25 37 1985 58.400 -150.900 33 5.3 Southern Alaska
4 21 17 41 57 1993 52.330 -170.120 33 5.0 Andreanoff Islands, Aleutians
4 21 20 36 34 1993 51.410 -175.580 33 5.1 Andreanoff Islands, Aleutians
4 21 16 55 27 1994 52.500 -172.700 33 5.0 Andreanoff Islands, Aleutians
4 21 15 50 3 1996 51.200 -178.500 28 5.1 Andreanoff Islands, Aleutians
4 21 4 35 18 2000 51.422 -178.137 33 6.2 Andreanoff Islands, Aleutians
4 21 17 18 57 2001 42.925 -111.395 1 5.4 Yellowstone/Wyoming
Felt in much of eastern Idaho, including Idaho Falls, Pocatello, Soda
Springs and Sugar City areas. Felt in part os western Wyoming including
Afton, Auburn and Jackson. Felt as far as the Air Traffic Control Tower at
Salt Lake City, Utah.

EARTHQUAKE LISTINGS

ASIA

O: 20APR2002 22:39:44 5.2N 124.5E Ms=5.2 GSSC MINDANAO, PHILIPPINE ISLANDS

O: 20APR2002 07:25:34 3.6N 127.0E mb=5.1 GSR TALAUD ISLANDS, INDONESIA

O: 21APR2002 00:04:24 4.9N 124.9E MB=4.5 GSR CELEBES SEA

O: 20APR2002 21:30 41.6N 142.1E Mj=4.7 NIED E_OFF_AOMORI_PREF, Japan
O: 20APR2002 21:30:30 42.2N 142.1E Mb=5.2 MIX HOKKAIDO, JAPAN, REGION

Note: This earthquake occurred near the IOC shadow zone boundary. The
FFA forecast from the Northern Chile earthquake had noted the possibility
of moderate FFA activity in this area:

"From the combination effects of these events several areas seem
likely to see events of Ms>=5.5 in the next 10 days. These include

...Southern Kuril Islands 43N 147E"

O: 20APR2002 08:47:57 22.8N 121.7E ML=5.6 TAI Taitung, Taiwan
O: 20APR2002 08:48:00 22.8N 121.7E MB=4.9 NEI TAIWAN REGION

O: 20APR2002 00:32:21 48.3N 146.9E MB=4.5 NEI SEA OF OKHOTSK
O: 20APR2002 00:32:18 47.7N 147.4E mb=4.5 GSR NORTHWEST OF KURIL ISLAND
Note: This earthquake occurred near the IOC shadow zone boundary at 145
degrees from the Mw 6.7 in Northern Chile on April 18, 2002. The
FFA forecast from the Northern Chile earthquake had noted the possibility
of moderate FFA activity in this area:

"From the combination effects of these events several areas seem
likely to see events of Ms>=5.5 in the next 10 days. These include

...Southern Kuril Islands 43N 147E"

O: 20APR2002 15:59:57 16.4S 173.2E MB=5.9 NEI FIJI ISLANDS REGION
Not Well Forecast from pulse considerations, this event was considered
likely from Far-field and geomagnetic effects.
The FFA forecast from Central Chile had noted:

"From the combination effects of these events several areas seem
likely to see events of Ms>=5.5 in the next 10 days. These include

..northern Vanuatu Is. 14S 167E"

and from The South Sandwich Islands:

"103-106 degrees***: ... No Vanuatu, Samoa "

The event also occurred in an area which was under seismic watch
from geomagnetic effects (within 30 degrees longitude of 180E) at the
time of the event.

SOUTH PACIFIC ISLANDS

CARIBBEAN/CENTRAL/SOUTH AMERICA

O: 20APR2002 07:30:33 12.4N 87.0W MC=3.4 SIS Nicaragua, Central America
O: 20APR2002 09:23:46 12.2N 86.8W MC=3.6 SIS Nicaragua, Central America

O: 19APR2002 23:02:38 17.0N 101.6W ML=3.9 SSN COSTA DE GUERRERO, MEXICO

O: 19APR2002 22:01:07 16.3N 95.1W ML=3.9 SSN OAXACA, MEXICO

O: 19APR2002 14:56:15 16.6N 100.4W ML=4.0 SSN COSTA DE GUERRERO, MEXICO

O: 20APR2002 07:30:33 12.4N 87.0W MC=3.4 SIS Nicaragua, Central America
O: 20APR2002 09:23:46 12.2N 86.8W MC=3.6 SIS Nicaragua, Central America

O: 20APR2002 09:24:09 10.8N 85.9W MC=3.3 CASC Costa Rica, Central America

NEW ZEALAND/AUSTRALIA

O: 20APR2002 00:48 38.7S 177.9E ML=3.5 IGNS SE of Gisborne, N.Z.

O: 20APR2002 16:57 40.4S 176.7E ML=3.7 IGNS SE of Porangahau, N.Z.

OCEANIA

EUROPE/MIDDLE EAST/AFRICA

U.S/CANADA

CALIFORNIA/NEVADA

O: 20APR2002 07:50:35 40.5N 122.0W Md=2.6 NCSN ESE of Redding, CA
O: 20APR2002 00:50:35 40.5N 122.0W ML=2.7 NCSN E of Anderson, CA

O: 20APR2002 09:14:09 39.4N 121.2W ML=2.0 NCSN NE of Loma Rica, CA

O: 20APR2002 16:17:59 40.7N 123.7W Ml=3.0 NCSN E of Eureka, CA
O: 20APR2002 09:17:59 40.7N 123.7W ML=3.0 NCSN SSW of Willow Creek, CA

PACIFIC NORTHWEST/CANADA

ROCKY MOUNTAIN AREA

O: 20APR2002 16:18:57 41.8N 111.0W ML=2.6 UUSN ENE of Randolph, UT
Note: This is an area of Utah where seismicity is generally fairly low.
Only 7 events have ever been recorded within 35 km of this epicenter
that were larger than today's earthquake. The last which was clearly
larger was a Ml 3.1 on Sept. 30, 1995. Earthquakes with Ml 2.5-2.7
have occurred in the area on 4/04/02. 22/02/02. 01/06/01, 20/12/00.
08/08/00, 08/09/99 and 30/09/95. So the daily probability of an event
of this size or larger in this area on a given day is about 0.003 or
odds of about 1 in 365.
The strong geomagnetic storm may have aided in adding energy to
enable a larger than normal event to occur.

EASTERN U.S./CANADA

O: 20APR2002 10:50:44 43.9N 74.2W MS=4.3 GSR NEW YORK
O: 20APR2002 10:50:44 44.5N 73.7W MB=5.1 NEI NEW YORK
O: 20APR2002 10:50:45 44.5N 73.7W MN=5.5 GSC NORTHERN N.Y STATE, U.S. FELT.
O: 20APR2002 11:04:40 44.5N 73.7W MN=4.2 GSC NORTHERN N.Y., U.S. AFTERSHOCK. PRELIMIN
O: 20APR2002 11:45:26 44.5N 73.7W MN=3.1 GSC NORTHERN N.Y., U.S. PRELIMINARY.
Note: This is the largest earthquake within 50 km of this event ever
recorded. A special report was posted earlier today on it. Daily summaries
for the past two days have included notes on the likelihood of a moderate
event in this area at this time. These were derived from the strong
effect of geomagnetic storms on this area as well as from FFA triggering
due to Chile and Mexico. For further details see the summary above.

O: 20APR2002 15:00:00 36.1N 89.4W ML=3.0 CERI N of Dyersburg, TN
Note: This event is the largest in the New Madrid seismic zone since
July 14, 2001 when an event of Ml 3.1 occurred. The area had been expected
to see FFA from the combination of earthquakes which occurred in Chile and
Mexico on April 18 as noted in the FFA forecast:

" Seismic activity may increase at:

continued micro-earthquakes in .. New Madrid MO"

The event is also close to the boundary of expected strongest effects
from recent geomagnetic storms, and the larger magnitude could well be
related to the strong geomagnetic storms of the past three days.

ALASKA

HAWAII